Field of the Invention
The present invention relates to a sprung vibration suppression device applied to a vehicle where driving/braking forces are generated vehicle wheels by a motor.
Description of the Related Art
Conventionally, there is known a so-called sprung damping control for controlling a motor for driving vehicle wheels to suppress sprung vibration. For example, a device disclosed in JP 2010-125986 A causes a motor to output a torque corresponding to a torque acquired by adding a damping control torque for suppressing the sprung vibration to a driving torque necessary to drive a vehicle. The damping control torque alternatively changes between positive and negative values in response to the sprung vibration. Thus, the torque output from the motor may change alternatively between the positive and negative values.
In this case, when the motor torque inverts, gears for reduction provided on a motor output shaft collide to each other through backlash therebetween to generate rattling noise.
Accordingly, when it is predicted that the motor torque alternatively changes between the positive and negative values, the device disclosed in the JP 2010-125987 A prohibits an addition of the damping control torque. Thereby, the generation of the rattling noise can be suppressed.